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adaptations in

artiodactyls

Pigs have four
toes on each foot, but only two of them touch the ground. Their limbs are short and not very advanced. Peccaries have lost the outer accessory hind hoof in the back leg. All four
toes of each foot of hippopotamuses touch the ground, and the terminal phalanges have nail-like hoofs. The
toe bones of camels are completely enclosed in hardened, horny hoofs, and lateral
toes spread...

ciconiiforms

Long legs and
toes are often an adaptation for wading. The
toes of herons are long and flexible, with just a hint of webbing for walking or standing on soft ground, the functional hind
toe aiding in perching. The hind
toe of storks and ibis is reduced and elevated, an adaptation for more walking and less perching. The relatively short front
toes of flamingos are completely webbed and the hind...

emus and cassowaries

As with many running birds, casuariiforms have only three
toes, the hind
toe having been lost. The inner
toe of cassowaries is armed with an elongated, daggerlike claw, making the foot a formidable weapon in kicking.

galliforms

...plan, being adapted for a primarily terrestrial existence. The feet and claws are large in all families, particularly so in the megapodes, reflecting their use for scratching and digging. The hind
toe is larger and more functional in groups, such as the cracids, that spend much time in trees; it is smaller in the more terrestrial groups, but in none has it been lost, as it has in terrestrial...

gruiforms

...cranes, many rails, and the limpkin, although the seriemas have hooked bills which are doubtless used in tearing up mammalian prey. The legs are rather long, reflecting a preference for walking. The
toes vary greatly—in the finfoots and coots they are lobed for swimming, in rails and the limpkin they are long and slender for walking on lily pads and other aquatic vegetation, and in...

lizards

Many modifications of the
toes occur in lizards. Some desert geckos, the iguanid
Uma, and the lacertid
Acanthodactylus have fringes on the
toes that provide increased surface area, preventing the lizard from sinking into loose desert sand. Arboreal geckos and anoles (
Anolis) have lamellae (fine plates) on the undersides of the
toes. Each lamella is made up of brushlike...

owls

All owls share the same general body plan. The wings are long and rounded, the tail short. The legs and
toes are of medium length and exceptionally strong for the size of the bird. Each
toe is provided with a needle-sharp, curved talon. The outer
toe points rearward when perching and is normally directed outward or backward in taking prey, providing the maximum possible
toe spread.

piciforms

Characteristic of all members of the order is the yoke-
toed (zygodactylous) foot in which the outer
toe (
toe IV) as well as the hind
toe (I) points to the rear. This was long considered an adaptation to climbing or perching on the vertical trunks of trees, but recent studies have shown that this type of
toe arrangement may really denote a generalized perching foot. Most of the strongly...

endurance-running

In 2009 Lieberman and several colleagues became the first scientists to test the endurance-running hypothesis empirically by calculating the effects of
toe length on running biomechanics. Their results suggested that reduced
toe length relative to body mass in bipeds had increased the efficiency of locomotion and lowered the metabolic costs of running. They reported that long
toes, a trait...

skeletal system

The phalanges—the
toe bones—of the foot have bases relatively large compared with the corresponding bones in the hand, while the shafts are much thinner. The middle and outer phalanges in the foot are short in comparison with those of the fingers. The phalanges of the big
toe have special features.

structure and function of nail

in the anatomy of humans and other primates, horny plate that grows on the back of each finger and
toe at its outer end. It corresponds to the claw, hoof, or talon of other vertebrates. The nail is a platelike, keratinous, translucent structure that consists of highly specialized epithelial cells. The nail grows from a deep groove in the dermis of the skin. All nail growth occurs at the nail’s...

type of digit

Primates have five digits, and most have developed fingernails and
toenails in the place of claws and hoofs. These digits tend to be capable of much independent, manipulative action. The human foot is specialized for bipedal locomotion—the
toes are shortened, relatively immovable, and nonmanipulative.